Series 90 (software platform)
The Series 90 (S90, formerly Hildon) is a platform for mobile phones that use the Symbian operating system (OS). It was developed by Nokia together with Psion. It was released in 2003 and was to be the platform for the Nokia 7700 which was cancelled, but S90 made it to market eventually in the Nokia 7710.
Nokia discontinued Series 90 as a platform, but merged its technology into S60. Although only one production Series 90 device was made, a form of the graphical user interface (GUI) continued on as Nokia's Hildon user interface in the Maemo shipped with Nokia Internet Tablets.